Pita Sebastian, Panzera Francisco, Sánchez Antonio, Panzera Yanina, Palomeque Teresa, Lorite Pedro
Sección Genética Evolutiva, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
Departamento de Biología Experimental, Área de Genética, Universidad de Jaén, Jaén, Spain.
PLoS One. 2014 Dec 5;9(12):e114298. doi: 10.1371/journal.pone.0114298. eCollection 2014.
The subfamily Triatominae, vectors of Chagas disease, comprises 140 species characterized by a highly homogeneous chromosome number. We analyzed the chromosomal distribution and evolution of repeated sequences in Triatominae genomes by Genomic in situ Hybridization using Triatoma delpontei and Triatoma infestans genomic DNAs as probes. Hybridizations were performed on their own chromosomes and on nine species included in six genera from the two main tribes: Triatomini and Rhodniini. Genomic probes clearly generate two different hybridization patterns, dispersed or accumulated in specific regions or chromosomes. The three used probes generate the same hybridization pattern in each species. However, these patterns are species-specific. In closely related species, the probes strongly hybridized in the autosomal heterochromatic regions, resembling C-banding and DAPI patterns. However, in more distant species these co-localizations are not observed. The heterochromatic Y chromosome is constituted by highly repeated sequences, which is conserved among 10 species of Triatomini tribe suggesting be an ancestral character for this group. However, the Y chromosome in Rhodniini tribe is markedly different, supporting the early evolutionary dichotomy between both tribes. In some species, sex chromosomes and autosomes shared repeated sequences, suggesting meiotic chromatin exchanges among these heterologous chromosomes. Our GISH analyses enabled us to acquire not only reliable information about autosomal repeated sequences distribution but also an insight into sex chromosome evolution in Triatominae. Furthermore, the differentiation obtained by GISH might be a valuable marker to establish phylogenetic relationships and to test the controversial origin of the Triatominae subfamily.
锥蝽亚科是恰加斯病的传播媒介，包含140个物种，其染色体数目高度一致。我们使用德氏锥蝽和侵扰锥蝽的基因组DNA作为探针，通过基因组原位杂交分析了锥蝽亚科基因组中重复序列的染色体分布和进化。杂交实验在它们自身的染色体以及来自两个主要族（锥蝽族和红猎蝽族）的六个属中的九个物种的染色体上进行。基因组探针明显产生两种不同的杂交模式，即分散分布或聚集在特定区域或染色体上。所使用的三种探针在每个物种中产生相同的杂交模式。然而，这些模式具有物种特异性。在亲缘关系较近的物种中，探针在常染色体异染色质区域强烈杂交，类似于C带和DAPI模式。然而，在亲缘关系较远的物种中未观察到这种共定位现象。异染色质Y染色体由高度重复序列构成，在锥蝽族的10个物种中保守，表明这是该群体的一个祖先特征。然而，红猎蝽族的Y染色体明显不同，支持了这两个族早期的进化二分法。在一些物种中，性染色体和常染色体共享重复序列，表明这些异源染色体之间存在减数分裂染色质交换。我们的基因组原位杂交分析不仅使我们能够获得关于常染色体重复序列分布的可靠信息，还能深入了解锥蝽亚科性染色体的进化。此外,通过基因组原位杂交获得的差异可能是建立系统发育关系以及检验锥蝽亚科有争议的起源的有价值标记。
